They are both equally as important.
Like someone already has said, the less well off form the back bone of our society, we are completely reliant on having poor people in our society. This is what annoys me when people say that poor people aren't hard working enough, are useless etc, without them you wouldn't be wealthy.
And then obviously the rich are important as well, while on an individual basis, they have more power, there are a lot less of them.